1. Field of the Invention
The invention relates to a method for producing a single-mode fiber, and more particularly to a method for producing a high strength and long coiling length single-mode fiber for submarine cable.
2. Description of the Related Art
Submarine cables work in a specific environment and the laying and maintenance thereof or accidental tension easily causes the destruction of fibers contained therein. Thus, fibers for submarine cables need higher strength in contrast with conventional fibers. Furthermore, to reduce the number of joints, the coiling length of the fibers should accord with the repeater spacing as possibly. The screening strain for conventional single-mode fibers for submarine cables is about 1%, which means a low strength, and the coiling length of conventional single-mode fibers for submarine cables is about 25 km, which means a large number of joints and high signal loss. To improve the service life and transmission efficiency of submarine cables, the strength and coiling length thereof need to be enhanced.